


A Mind of Their Own

by TobytheWise



Series: 2019 Kinktober [2]
Category: Shadowhunters (TV)
Genre: 69 (Sex Position), Alternate Universe - Canon Divergence, Bottom Alec, Fluff, Frottage, Insecure Magnus Bane, Light Angst, M/M, Rimming, Tentacle Sex, Tentacles, Top Magnus Bane, Warlock Marks
Language: English
Status: Completed
Published: 2019-10-03
Updated: 2019-10-25
Packaged: 2020-11-07 20:27:27
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,065
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20823311
Author URL: https://archiveofourown.org/users/TobytheWise/pseuds/TobytheWise
Summary: Magnus has a secret. He has two warlock marks. His cat eyes and someone this father 'gifted' him a long time ago. Alec is ready to take things 'to the next step' but Magnus is scared of how he'll react to THEM.Unsurprised by anyone, Alec LOVES them as much as they love him.





	1. Chapter 1

**Author's Note:**

> TENTACLES!   
Written for day three of Kinktober, prompt: tentacles.   
This story has two parts. The second part will be posted on day 25.   
I hope you enjoy :D

Magnus sighs as he rolls his shoulders. With a thought, his warlock mark disappears before his very eyes. He turns away from the mirror just as his wards ripple with someone’s presence. And not just someone, but Alexander. 

Magnus’ belly fills with excitement. His warlock mark twitch with excitement as well and it makes nervous energy thrum through Magnus’ veins. He runs his fingers over the bridge of his nose. He hadn’t discussed his  _ extra _ warlock mark with Alec yet. Too scared of his reaction. They’re disgusting, literally given to him with the knowledge that no one could look at them and keep on loving Magnus. 

Magnus shakes his head as he thinks about that day. When he was still a young warlock, his father had tried to groom him, make him do bad things. When he’d tried to get away from Asmodeus, it didn’t go as planned. Asmodeus was angry and decided to use his magic to twist and corrupt Magnus’ warlock mark. He always kept them glamoured, hidden from anyone and everyone. But they’re not like other warlock marks. They’re almost their own entity, having thoughts and feelings of their own outside of what Magnus wants. 

Even now, standing at the door, waiting for Alec, they twitch and sway in a way that Magnus recognizes as excitement. They  _ like _ Alexander. Not that he blames them, he  _ is _ lovely. But every single day it gets harder and harder to keep them glamoured around the Shadowhunter. 

With a flick of his wrist, Magnus opens the door. His stomach erupts in butterflies as soon as his eyes land on Alec. He flicks his left wrist up, using the back of his hand to swat one of  _ them _ away as it tries to inch close enough to touch Alexander. 

“Hello, darling,” he greets, leaning forward and kissing Alec’s cheek. Alec turns his head, taking Magnus’ lips in a heated kiss. Magnus is expecting a lot of things when he realized Alec was here but  _ this _ wasn’t it. 

Magnus hands come up to Alec’s broad chest as he opens his lips, accepting Alec’s prodding tongue into his mouth. Their tongues caress each other and it makes Magnus’ body heat up with lust. His hands run over Alec’s chest before landing on his neck, holding him in place as they kiss. 

It’s the feeling of one of Alec’s hands moving towards his back that has Magnus jumping back, breaking contact. “Fuck,” he murmurs to himself, his breath coming out in pants. His thumb touches his lips which are still wet with Alec’s spit. “I’m- I uh-” Magnus tries before cutting himself off and taking a breath. He tries again, “what’s going on, Alexander?”

Their eyes meet and Magnus shivers, seeing the amount of desire and lust in Alec’s eyes. He wants Magnus. And the feeling is mutual. But he can’t. 

“I just thought we could, ya know. Take the next step,” Alec explains, stepping back into Magnus’ space. His big hands gently cup Magnus’ hips. 

“Oh,” Magnus says quietly. “You mean the sex step.”

Alec’s hands tighten around his hips. “Yes. Unless you don’t want that?” Alec asks slowly. 

Magnus looks up into Alec’s eyes. “Trust me,” he says, “I really, really want to.” Then he pauses, willing his glamour to stay in place as they all grow in excitement at the idea of having Alexander closer. “But I’m not sure it’s the best idea.”

Alec’s face breaks out into a wide smile. “It’s okay,” he whispers before diving down, kissing Magnus’ lips once more. “We both want this.”

Magnus’ resolve cracks under Alec’s ministrations. Those talented lips find this throat, leaving gentle kisses and stinging nips. They make his knees weak but those strong, Shadowhunter arms keep him on his feet. Alec crowds against him, pushing him back until he finds the couch, falling down and pulling Alec down into his lap. 

Alec’s hands go straight to Magnus’ hair, running through the long strands. Magnus moans, the sound radiating through his chest as they make out. Alec’s little movements with his hips are driving Magnus crazy, his ass rubbing against Magnus’ hard cock. 

Magnus’ heart races, his hands finding Alec’s hips, helping him to move with more purpose, bringing them both pleasure. 

“Fuck, Magnus,” Alec murmurs, his voice even deeper than usual. Magnus’ cock twitches where it’s trapped against Alec’s ass. They’ve only just started and already Magnus feels out of control. 

“Shirt. Shirt off,” Magnus grits out through clenched teeth. He wants his hands on every inch of Alec and admire his toned body. Alec pulls back from kissing Magnus’ throat, pulling his shirt over his head and tossing it onto the floor behind him. Magnus’ hands find Alec’s stomach, running up the expanse of pale skin before finding his chest. He runs his fingers through Alec’s chest hair, loving how it feels under his palms. 

“You too, Magnus,” Alec whispers, helping Magnus with his shirt. The moment the hot skin of their chests brush, Magnus sucks in a sharp breath, his body lighting up. 

Magnus tilts his head back against the back of the couch and Alec uses it as an opportunity to explore Magnus’ chest. His hands move over Magnus’ abs before coming up to tweak his nipples. “Alexander,” he moans as pleasure zings through him. Alec’s mouth slides across his throat before sucking on his adam’s apple. 

Magnus is so overwhelmed with Alec, Alec,  _ Alec _ , that he doesn’t even realize his glamour has fallen away until Alec freezes above him. Magnus opens his eyes to find Alec staring over his shoulders, his eyes wide with surprise. 

Magnus pushes Alec off his lap and onto the couch before he stands up, turning away from Alec. His fingers rub at his eyes as he takes deep breaths, trying to get himself under control. “Fuck,” he hisses. How did he let this happen?  _ Fucking traitors, _ he interanally glares at his marks. 

“Magnus,” Alec says softly as he stands up, gently touching Magnus shoulder. Magnus turns around, unable to meet Alec’s disgusted gaze. 

“I’m sorry if I’ve frightened you,” he says. “You know you’re dating a Warlock but I didn’t want you to see how much of a  _ monster _ I am.” His self loathing washes over him, overwhelming Magnus. He wants to shrink in on himself and disappear. For a moment, he contemplates opening a portal but before he can, two strong hands are cupping his cheeks. 

“Hey,” Alec whispers, his voice the opposite of what Magnus expected. Finally, he opens his eyes. “Magnus. You are far from a monster. You’re-” Alec licks his lips, his eyes flicking between Magnus’. “You’re beautiful.”

Magnus lets out a long breath before asking, “how can you say that? You  _ saw _ .”

Alec’s eyes look over Magnus’ head again as he says, “I have. And nothing about you is ugly, Magnus. They’re a part of you, just like your eyes.” His thumb runs over Magnus’ cheekbone and Magnus can’t find anything but love and adoration on Alec’s face. 

“They were  _ a gift _ from my father,” he explains. “More like a curse if you ask me.” Magnus shrugs his shoulders, letting his glamour fall away. Almost like they now have permission, two of Magnus’ tentacles, one from each side, duck forward. One buries itself in Alec’s hair while the other gently touches Alec’s cheek in a mirror of what Alec’s hand is doing. 

Magnus flushes, embarrassment flooding his being. “Seriously,” he chastizes but Alec just blushes, a wide smile breaking out across his face. 

“They’ve got a mind of their own,” Alec says in wonder, his other hand coming up, his pointer finger touching the tip of another tentacle. 

“They do,” Magnus sighs. “And they like you. Have since the day we first met.”

“They’ve wanted to touch me since then?” Alec asks, his head tilting ever so slightly. “Why didn’t you let them?”

Magnus looks at Alec, sucking his lips in. “Are you joking? Because this is crazy. I have a twisted curse attached to my back. I’m literally a tentacle monster, Alec.” Just then, one of his tentacles slaps his shoulder. “I’m sorry,” he says, huffing at the tentacle, “but it’s true.”

Alec bites his bottom lip before asking, “can you turn around?”

Magnus raises a brow before doing as he’s asked. He folds his arms over his chest, sulking over the fact that his tentacles are finally getting what they’ve wanted for  _ so _ long. Alec lets out a huff of amusement as his tentacles tentatively begin to touch him. It’s not until Alec lets out a moan that Magnus takes a step away, turning back around. 

What he sees takes his breath away. Alec is panting, his cheeks deliciously flushed. “Is this okay?” Magnus asks. 

“More than,” Alec answers, stepping into Magnus’ space and kissing him. Despite their little break, within seconds, they’re right back to where they were, touching and caressing and kissing and grinding against each other. Magnus’ tentacles reach out, touching Alec’s sides, one of them reaches back, groping Alec’s ass. 

“If they’re too much just let me know,” Magnus says between sloppy kisses. 

“Never,” Alec gets out huskily. “Love them, too.”

Four of his six tentacles work at getting them out of their pants and for once, Magnus is on board with their plan. He shoves Alec down onto the couch, crawling between his legs. 

“Fuck, Magnus,” Alec moans, tilting his head back. Magnus leans down, running his tongue over Alec’s deflect rune, shivering as Alec lets out a low groan. He grind his hips down, whining as their cocks line up and rub against each other. 

Magnus leans up enough to reach a hand between them, only to have his hand slapped away as one of his tentacles slides between them instead. It wraps around both of their cocks, making a tight tunnel for them to fuck into. 

“Oh,” Alec breathes as he stares down between them. “By the Angel. Fuck, that feels so good,” he says, sounding surprised. It makes Magnus smile before he’s diving down, plunging his tongue into Alec’s mouth. 

Pleasure races down Magnus’ spine, his balls drawing up tight as his orgasm barrels towards him. “Alexander,” he gasps out. They pant against each other’s lips, their eyes locked as their hips move against each other. 

With his eyes glued to Magnus, Alec reaches up, taking one of Magnus’ tentacles into his palm, bringing it down to his lips. He kisses it gently and it makes Magnus shudder in pleasure. Alec sees his reaction and smirks before opening his mouth and taking the very tip between his lips, swirling his tongue around the sucker at the tip. 

“Jesus,” Magnus groans. It feels so good to have Alec touching him like this, so much a part of Magnus, part of his magic, his very  _ being _ . “Fuck,” he gasps out as his orgasm overtakes him. The tentacle around their cocks tightens, wringing every ounce of pleasure from Magnus, milking every drop from his dick. 

“Magnus,” Alec gets out, his eyes closing, his mouth dropping slack. “I’m so close.”

Although his tentacles are  _ mostly _ their own entity, he still has control of them when he needs to. Right now, he wants nothing more than to bring Alec more pleasure, to send him flying over the edge. He uses one of his tentacles to circle Alec’s nipples before using a sucker to latch onto each nipple. 

Alec’s body bows, his corded muscles all straining as he cries out and comes between them, adding his hot cum to the pool already on his belly. What a sight Alexander makes. Magnus is overcome by how beautiful his lover is, how understanding and gracious. 

“I love you,” he murmurs before collapsing against Alec’s chest, burying his face against his throat. He’s overcome with emotion as he murmurs over and over again, “I love you. I love you.”

His tentacles wrap around his arms and shoulders, making Magnus feel like he’s being hugged from the front and the back. They’re holding him just as Alec is holding him. It’s fucking perfect. 

“I love you, too,” Alec whispers, kissing the side of his head. “I love you so much. Thank you for sharing this with me.”

Magnus snorts. “Like I really had a choice.”

“I’m glad they decided to show themselves.” Magnus can feel Alec smirk against his shoulder as he adds, “and I look forward to getting to know them.  _ Intimately. _ ”


	2. Chapter 2

**Summary for the Chapter:**

> Written for kinktober day 25, prompt: monsterfucker.

Alec huffs against Magnus’ mouth, frustrated that there’s still so many layers of clothes between them. “Clothes,” he whines, barely containing his noise of glee when Magnus uses his magic to strip them both. Finally, their naked skin touch. 

They’d just gotten home from their date, both a little bit tipsy. Alec feels warm all over, a smile across his lips as they stumble down the hall towards Magnus’ room. 

Once inside, Alec doesn’t waste any time. He shoves Magnus forward until he falls on his back on the bed. Magnus scoots back, his eyes never leaving Alec. He lifts his hands, gesturing for Alec to join him. And of course, Alec does. 

Feeling bold, and ridiculously turned on, Alec crawls over Magnus’ body before turning around. The gasp he hears from Magnus makes him shiver as he pushes his ass back until it’s over Magnus’ face. 

“Oh fuck. Look at you,” Magnus whispers as his hands slide over the backs of Alec’s thighs, making him shudder. 

Alec falls forward onto his elbows, at the perfect height to suck Magnus’ cock. He licks along the length before taking the tip into his mouth. He hums happily as the taste, sending vibrations through Magnus’ cock. 

Alec feels Magnus shift below him before curious tentacles begin to caress Alec’s sides. “Yes,” he hisses, loving Magnus warlock mark. He can’t help but smile, feeling their tentative touches, slowly growing more and more bold as they explore Alec’s skin. 

Magnus pulls Alec’s cheeks apart before diving in with his tongue. He swirls it around Alec’s hole, forcing a moan from his throat. Fuck, Magnus is so good at that, his tongue is literally magic, just like the rest of Magnus. 

Alec tries to focus on the dick in front of him, lavishing it with attention, but he keeps having to pull off to moan or whine as Magnus’ tongue works him over. Combined with the attention of his tentacles all over Alec’s body, Alec can’t fucking concentrate! Every nerve in his body feels like it’s on fire, pleasure racing through him. 

“Fuck, Magnus,” Alec cries out as two tentacles focus on his chest, latching their suckers to his nipples in a way that drives him fucking wild. He swivels his hips slightly, riding Magnus’ tongue, whining high as he feels a tentacle slowly circle his rim. “Yes. Please,” he gasps out. He  _ needs _ . 

The tentacle slowly pushes in. The tip is slim and slips in easily, slowly stretching him as it goes deeper. 

“So beautiful,” Magnus says, watching the tentacle move in his ass. It makes Alec flush all the way down his chest. He sits up, just letting Magnus pleasure him. One of the tentacles touches his lips, tracing the seam. Alec opens his lips, letting it in, sucking on the very tip before swirling his tongue around the sucker and reveling in the high pitch whine it forces from Magnus below him. 

It’s overwhelming, having so much attention on him. Alec’s had time to get used to the tentacles in general but having them here while they have sex, it’s something else. Alec loves it, fucking  _ craves _ it. 

“Turn around,” Magnus says gently, leaving a stinging slap against one of Alec’s cheeks. “Want you to ride me.”

Alec nods his head as he shifts around, kneeling over Magnus’ pelvis. He reaches back, guiding Magnus slick cock to his hole before slowly sliding down. He tilts his head up towards the ceiling, closing his eyes in bliss as he’s stuffed full. Despite the tentacle stretching him, there’s still a burn as Alec sinks down. It’s fucking perfect. 

Alec leans down, wrapping one of his hands along the side of Magnus’ throat before kissing him long and hard. He tilts his ass up just right to give Magnus the best angle to fuck up into him. Fuck, it’s so good and he’s left panting against Magnus’ mouth, their foreheads pressed together. 

Alec lets out a gasp of pleasure as a tentacle wraps around his cock, stroking him in time with Magnus’ thrusts. Magnus’ hands grip him tightly around his hips and it grounds him, keeps him from flying off into the blissful abyss. 

“You feel amazing,” Magnus whispers against his lips and when Alec opens his eyes, he finds himself lost in Magnus’ golden cat eyes. “So tight around me. So willing to touch my tentacles. How’d I ever get so fucking lucky?”

Alec pants, trying to catch his breath before saying, “I’m the lucky one. Look what you do to me.”

Just then, the tentacle around his cock shifts until one of it’s suckers lands on his cockhead. It seems to suck the orgasm right out of him. “Magnus,” he grits out through clenched teeth as pleasure washes over him. The dick in his ass continues to grind against his prostate, milking every drop of cum from his balls. 

“Beautiful,” Magnus murmurs as his hips pick up speed. Alec buries his face against Magnus’ throat as he fucks him, using Alec’s body for his pleasure. 

Magnus cries out as his hips still. Alec feels the warmth in his ass signaling Magnus’ orgasm and he clenches, trying to bring Magnus as much pleasure as he’s given Alec. 

Tentacles slowly caress his sweaty back and Alec practically  _ melts _ against Magnus’ chest. If he were a cat he’d be purring right about now with how relaxed and sated he feels. 

“I love you,” Magnus whispers. 

“I love you, too,” Alec says, placing a gentle kiss against Magnus’ lips. Then a tentacle comes into view and Alec sits up enough to place a gentle kiss against it. “And you,” he says before another takes its place. He smiles as he kisses this one. “And you.” So on until all eight of them have been given their own personal kiss and I love you.”

“You spoil them,” Magnus says with a teasing smile. 

Alec shrugs. “You deserve it.”


End file.
